Latest Publications

@article{hyzdalova_aryl_2018,

title = {Aryl Hydrocarbon Receptor-Dependent Metabolism Plays a Significant Role in Estrogen-Like Effects of Polycyclic Aromatic Hydrocarbons on Cell Proliferation.},

author = {Martina Hýžd'alová and Jakub Pivnicka and Ondrej Zapletal and Gerardo Vázquez-Gómez and Jason Matthews and Jirí Neca and Katerina Pencíková and Miroslav Machala and Jan Vondrácek},

doi = {10.1093/toxsci/kfy153},

issn = {1096-0929 1096-6080},

year  = {2018},

date = {2018-10-01},

journal = {Toxicological sciences : an official journal of the Society of Toxicology},

volume = {165},

number = {2},

pages = {447–461},

abstract = {Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that interact in a complex manner with both the aryl hydrocarbon receptor (AhR) and estrogen receptors (ER). Their potential endocrine-disrupting activities may depend on both inhibitory AhR-ER cross-talk and on AhR-dependent metabolic production of estrogenic PAH metabolites. Here, we analyzed the impact of AhR on estrogen-like effects of PAHs, such as benzo[a]pyrene (BaP), in particular, on control of cell cycle progression/cell proliferation. Using AhR knockout variant of estrogen-sensitive human breast cancer MCF-7 cells (MCF-7 AhRKO cells), we observed that the AhR-dependent control of cytochrome P450 family 1 (CYP1) expression played a major role in formation of estrogenic BaP metabolites, most notably 3-OH-BaP, which contributed to the ER-dependent induction of cell cycle progression/cell proliferation. Both BaP metabolism and the BaP-induced S-phase transition/cell proliferation were inhibited in MCF-7 AhRKO cells, whereas these cells remained sensitive towards both endogenous estrogen 17β-estradiol or hydroxylated BaP metabolites. BaP was found to increase the activity of ER-dependent luciferase reporter gene in wild-type MCF-7 cells; however, unlike its hydroxylated metabolite, BaP failed to stimulate luciferase activity in MCF-7 AhRKO cells. Similarly, estrogen-like effects of other known estrogenic PAHs, such as benz[a]anthracene or 3-methylcholanthrene, were diminished in MCF-7 AhRKO cells. Ectopic expression of human CYP1A1 and CYP1B1 enzymes partly restored both BaP metabolism and its effects on cell proliferation. Taken together, our data suggest that the AhR-dependent metabolism of PAHs contributes significantly to the impact of PAHs on cell proliferation in estrogen-sensitive cells.},

note = {Place: United States},

keywords = {Aryl Hydrocarbon/genetics/*metabolism, Cell Culture Techniques, Cell Cycle/drug effects/genetics, Cell Proliferation/*drug effects/genetics, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1/genetics/metabolism, Endocrine Disruptors/metabolism/*toxicity, Estrogen/genetics/metabolism, Gene Expression/drug effects, Gene Knockdown Techniques, Genes, Genetic Vectors, Humans, MCF-7 Cells, Plasmids, Polycyclic Aromatic Hydrocarbons/metabolism/*toxicity, Receptors, Reporter, Transfection},

pubstate = {published},

tppubtype = {article}

}

@article{steinmetz_oncogene_2014,

title = {The oncogene EVI1 enhances transcriptional and biological responses of human myeloid cells to all-trans retinoic acid.},

author = {Birgit Steinmetz and Hubert Hackl and Eva Slabáková and Ilse Schwarzinger and Monika Smějová and Andreas Spittler and Itziar Arbesu and Medhat Shehata and Karel Souček and Rotraud Wieser},

doi = {10.4161/15384101.2014.946869},

issn = {1551-4005 1538-4101},

year  = {2014},

date = {2014-01-01},

journal = {Cell cycle (Georgetown, Tex.)},

volume = {13},

number = {18},

pages = {2931–2943},

abstract = {The product of the ecotropic virus integration site 1 (EVI1) gene, whose overexpression is associated with a poor prognosis in myeloid leukemias and some epithelial tumors, regulates gene transcription both through direct DNA binding and through modulation of the activity of other sequence specific transcription factors. Previous results from our laboratory have shown that EVI1 influenced transcription regulation in response to the myeloid differentiation inducing agent, all-trans retinoic acid (ATRA), in a dual manner: it enhanced ATRA induced transcription of the RARβ gene, but repressed the ATRA induction of the EVI1 gene itself. In the present study, we asked whether EVI1 would modulate the ATRA regulation of a larger number of genes, as well as biological responses to this agent, in human myeloid cells. U937 and HL-60 cells ectopically expressing EVI1 through retroviral transduction were subjected to microarray based gene expression analysis, and to assays measuring cellular proliferation, differentiation, and apoptosis. These experiments showed that EVI1 modulated the ATRA response of several dozens of genes, and in fact reinforced it in the vast majority of cases. A particularly strong synergy between EVI1 and ATRA was observed for GDF15, which codes for a member of the TGF-β superfamily of cytokines. In line with the gene expression results, EVI1 enhanced cell cycle arrest, differentiation, and apoptosis in response to ATRA, and knockdown of GDF15 counteracted some of these effects. The potential clinical implications of these findings are discussed.},

note = {Place: United States},

keywords = {*Oncogenes, acute myeloid leukemia, acute promyelocytic leukemia, all-trans retinoic acid, AML, APL, Apoptosis, Apoptosis/drug effects, Ar, ATRA, ATRA regulation, Cell Cycle, Cell Cycle Checkpoints/drug effects, Cell Differentiation/drug effects, dimethyl sulfoxide, DMSO, DNA-Binding Proteins/genetics/*metabolism, Down-Regulation/drug effects, Em, Epithelial Cells/drug effects/metabolism, Er, EVI1, EVI1 modulation, EVI1 regulation, false discovery rate, FBS, FC, FDR, fetal bovine serum, fold change, GDF15, Gene Expression Profiling, Gene Knockdown Techniques, Genetic/*drug effects, GFP, green fluorescent protein, Growth Differentiation Factor 15/genetics/metabolism, HL-60 Cells, Humans, mcoEvi1, MDS, MDS1 and EVI1 Complex Locus Protein, murine codon optimized Evi1, myelodysplastic syndrome, Myeloid Cells/drug effects/*metabolism, myeloid differentiation, penicillin streptomycin glutamine, Proto-Oncogenes/genetics, PSG, RAR, RARE, Real-Time Polymerase Chain Reaction, Reproducibility of Results, retinoic acid receptor, retinoic acid response element, SE, standard error, Transcription, Transcription Factors/genetics/*metabolism, Tretinoin/*pharmacology},

pubstate = {published},

tppubtype = {article}

}

@article{faust_ahr-mediated_2013,

title = {AhR-mediated changes in global gene expression in rat liver progenitor cells.},

author = {Dagmar Faust and Jan Vondráček and Pavel Krčmář and Lenka Smerdová and Jiřina Procházková and Eva Hrubá and Petra Hulinková and Bernd Kaina and Cornelia Dietrich and Miroslav Machala},

doi = {10.1007/s00204-012-0979-z},

issn = {1432-0738 0340-5761},

year  = {2013},

date = {2013-04-01},

journal = {Archives of toxicology},

volume = {87},

number = {4},

pages = {681–698},

abstract = {Although the tumor-promoting effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), coplanar polychlorinated biphenyls (PCBs), and related compounds in liver tissue are primarily attributed to the activation of the aryl hydrocarbon receptor (AhR), the underlying molecular mechanisms are still unclear. Liver progenitor (oval) cells have been suggested to constitute a potential target for hepatocarcinogenic chemicals. To better understand AhR-driven pathways, we analyzed the transcriptional program in response to coplanar PCB 126 in contact-inhibited rat liver progenitor WB-F344 cells using high-density microarrays. After 6-h treatment, we identified 145 significantly deregulated genes considered to be direct AhR-dependent target genes. The number of differentially regulated genes increased to 658 and 968 genes after 24 and 72 h, respectively. Gene ontology analysis revealed that these genes were primarily involved in drug and lipid metabolism, cell cycle and growth control, cancer developmental processes, cell-cell communication, and adhesion. Interestingly, the Wnt and TGF-β signaling pathways, both being involved in developmental and tumorigenic processes, belonged to the most affected pathways. AhR- and ARNT-dependent regulation of selected target genes of interest was then confirmed using TCDD as a model AhR agonist, together with pharmacological inhibition of the AhR and by RNA-interference techniques. We demonstrated AhR-dependent regulation of emerging and novel AhR target genes, such as Fst, Areg, Hbegf, Ctgf, Btg2, and Foxq1. Among them, the transcription factor Foxq1, recently suggested to contribute to tumor promotion and/or progression, was found to be regulated at both mRNA and protein levels by AhR/ARNT activation.},

note = {Place: Germany},

keywords = {Animals, Aryl Hydrocarbon/*genetics/metabolism, Cell Line, Epithelial Cells/drug effects/*metabolism/pathology, Estrogen Antagonists/toxicity, Gene Expression Regulation/drug effects/*genetics, Gene Knockdown Techniques, Liver/drug effects/*metabolism/pathology, Oligonucleotide Array Sequence Analysis, Polychlorinated Biphenyls/toxicity, Rats, Receptors, Stem Cells/drug effects/*metabolism/pathology},

pubstate = {published},

tppubtype = {article}

}

@article{andrysik_aryl_2013,

title = {Aryl hydrocarbon receptor-mediated disruption of contact inhibition is associated with connexin43 downregulation and inhibition of gap junctional intercellular communication.},

author = {Zdeněk Andrysík and Jiřina Procházková and Markéta Kabátková and Lenka Umannová and Pavlína Simečková and Jiří Kohoutek and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1007/s00204-012-0963-7},

issn = {1432-0738 0340-5761},

year  = {2013},

date = {2013-03-01},

journal = {Archives of toxicology},

volume = {87},

number = {3},

pages = {491–503},

abstract = {The aryl hydrocarbon receptor (AhR) contributes to the control of cell-to-cell communication, cell adhesion, migration or proliferation. In the present study, we investigated the regulation of connexin43 (Cx43) and Cx43-mediated gap junctional intercellular communication (GJIC) during the AhR-dependent disruption of contact inhibition in non-tumorigenic liver epithelial cells. The contact inhibition of cell proliferation is a process restricting the cell division of confluent non-transformed cells, which is frequently abolished in cancer cells; however, the mechanisms contributing to its disruption are still only partially understood. Disruption of contact inhibition, which was induced by toxic AhR ligands 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or polycyclic aromatic hydrocarbons in epithelial WB-F344 cells, reduced Cx43 protein levels, possibly via enhanced proteasomal degradation, significantly decreased the amount of gap junction plaques and downregulated GJIC, in an AhR-dependent manner. Although both intracellular and membrane Cx43 pools were markedly reduced in cells released from contact inhibition by TCDD, siRNA-mediated Cx43 knock-down was not sufficient to stimulate proliferation in contact-inhibited cells. Our data suggest that downregulation of Cx43/GJIC in non-transformed epithelial cells is an inherent part of disruption of contact inhibition, which occurs at the post-transcriptional level. This process runs in parallel with alterations of other forms of cell-to-cell communication, thus suggesting that toxic AhR agonists may simultaneously abrogate contact inhibition and reduce GJIC, two essential mechanisms linked to deregulation of cell-to-cell communication during tumor promotion and progression.},

note = {Place: Germany},

keywords = {Animals, Aryl Hydrocarbon/*agonists/genetics/metabolism, Benz(a)Anthracenes/toxicity, Carcinogens/*toxicity, Cell Communication/*drug effects, Cell Line, Cell Proliferation, Cell Transformation, Connexin 43/genetics/*metabolism, Contact Inhibition/*drug effects, Dose-Response Relationship, Down-Regulation, Drug, Epithelial Cells/*drug effects/metabolism/pathology, Fluorenes/toxicity, Gap Junctions/*drug effects/metabolism/pathology, Gene Knockdown Techniques, Indoles/pharmacology, Ligands, Liver Neoplasms/chemically induced/metabolism/pathology, Liver/*drug effects/metabolism/pathology, Neoplastic/chemically induced/metabolism/pathology, Phloroglucinol/analogs & derivatives/pharmacology, Phosphorylation, Polychlorinated Dibenzodioxins/toxicity, Proteasome Endopeptidase Complex/metabolism, Rats, Receptors, RNA Interference, Signal Transduction/*drug effects, Time Factors, Transfection},

pubstate = {published},

tppubtype = {article}

}